[Deepin-Kernel-SIG] [Upstream] [linux 6.6-y] net: stmmac: Convert prefetch() to net_prefetch() for rece…

[opsiff]

…ived frames

mainline inclusion
from mainline-v6.14-rc1
category: performance

The size of DMA descriptors is 32 bytes at most.
net_prefetch() for received frames, and keep prefetch() for descriptors.

This patch brings ~4.8% driver performance improvement in a TCP RX throughput test with iPerf tool on a single isolated Cortex-A65 CPU core, 2.92 Gbits/sec increased to 3.06 Gbits/sec.

Suggested-by: Joe Damato [email protected]

Reviewed-by: Yanteng Si [email protected]
Reviewed-by: Larysa Zaremba [email protected]
Reviewed-by: Joe Damato [email protected]

Summary by Sourcery

Enhancements:

• Improve driver performance by ~4.8% in TCP RX throughput tests by using net_prefetch() for received frames and prefetch() for descriptors.

[sourcery-ai]

Reviewer's Guide by Sourcery

This pull request optimizes the stmmac driver by replacing prefetch() with net_prefetch() for received frames, which improves performance. The change is focused on the receive path of the driver.

Sequence diagram for optimized network frame prefetch flow

sequenceDiagram
    participant Driver as STMMAC Driver
    participant Memory as Memory System
    participant CPU as CPU Cache

    Note over Driver,CPU: Optimized prefetch flow
    Driver->>Memory: DMA sync for CPU
    Driver->>CPU: net_prefetch(frame data)
    Note right of CPU: Optimized prefetch<br/>specifically for<br/>network frames
    Driver->>Memory: Initialize XDP buffer
    Driver->>Memory: Prepare XDP buffer

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Flow diagram for network frame processing optimization

flowchart LR
    start[Start Frame Processing]
    sync[DMA Sync for CPU]
    prefetch[net_prefetch Frame Data]
    xdp_init[Initialize XDP Buffer]
    xdp_prep[Prepare XDP Buffer]

    start --> sync
    sync --> prefetch
    prefetch --> xdp_init
    xdp_init --> xdp_prep

    style prefetch fill:#f9f,stroke:#333,stroke-width:2px
    note[Note: Optimized prefetch<br/>for network frames]
    prefetch -.-> note

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File-Level Changes

Change	Details	Files
Replaced prefetch() with net_prefetch() for received frames.	Changed prefetch() to net_prefetch() when prefetching received frame data.	drivers/net/ethernet/stmicro/stmmac/stmmac_main.c

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[sourcery-ai]

Hey @opsiff - I've reviewed your changes and they look great!

Here's what I looked at during the review

• 🟢 General issues: all looks good
• 🟢 Security: all looks good
• 🟢 Testing: all looks good
• 🟢 Complexity: all looks good
• 🟢 Documentation: all looks good

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[deepin-ci-robot]

[APPROVALNOTIFIER] This PR is NOT APPROVED

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